The Kidde Battery Powered Carbon Monoxide & Smoke Alarm with Voice Commands combines two safety devices into one. It has a voice warning system that announces Fire, Carbon Monoxide, Low Battery, and Smart Hush. It is powered by (3)AA batteries and will work during power outages. It has two LED indicators, a test button, a low battery warning, battery safeguard and a HUSH feature to temporarily silence nuisance alarms. The voice alarm eliminates any confusion of the type of alarm that is sounding wih simple verbal commands. Children have been shown to respond to a voice command better than a horn type alarm alone. No wiring required for installation. 5.75 inch diameter. Mount on wall or ceiling.